Field of the Invention
The present invention relates to a display control apparatus, a method of controlling the same, and a storage medium, and more particularly to a display control apparatus that performs time-line display when reproducing a moving image including images recorded at different recording speeds.
Description of the Related Art
As a type of reproduction apparatuses that reproduce an image or the like, a reproduction apparatus is generally known which performs so-called time-line display in which images of frames forming a moving image are extracted for display at time intervals designated by a user (see e.g. Japanese Laid-Open Patent Publication (Kokai) No. 2010-263374). Let it be assumed, for example, that a moving image recorded at a rate of 30 frames per second (hereinafter referred to as 30 FPS) is subjected to a time-line display at intervals of one second. In this case, the time-line display is performed by extracting images of frames forming the moving image every 30 frames, and displaying the extracted images, in a line, in a reduced size.
By performing the time-line display, a user can efficiently grasp what kind of images were recorded in a moving image. Further, the time-line display is also useful in searching for a target scene (image) when a user performs an editing operation, such as cutting.
On the other hand, when a moving image is shot, there is a case where scenes recorded at different recording speeds are included in one moving image. This shooting provides such an effect that a specific part of the moving image is slowly reproduced, and hence it is possible to obtain a more impressive moving image.
However, when a moving image including images recorded at a plurality of different recording speeds is subjected to time-line display, there arise the following problems:
In a case where the time-line display is performed at time intervals designated by a user, frame extraction is performed at a frame interval determined with reference to a normal recording speed part of the moving image. In this case, if frame extraction is performed at the determined frame interval with respect to images recorded at another recording speed, the time-line display of the images is not performed at the designated time intervals. For example, assuming that the time-line display at intervals of one second is performed with respect to a moving image including a normal recording speed part which is recorded at 30 FPS, in this case, images of the frames forming the moving image are each extracted every 30 frames. Further, when the same processing is performed for images recorded at ½× speed, the images are extracted not at the intervals of one second, but at the intervals of 0.5 seconds, with respect to the real time in recording the images.
As described above, one moving image includes images which, when subjected to the time-line display, are displayed at the time intervals designated by the user, and images which, when subjected to the time-line display, are not displayed at the time intervals designated by the user. This gives uncomfortable feeling to a user.
Further, assuming that a moving image of a scene including images recorded at a plurality of different recording speeds and a moving image of the same scene recorded only at the normal recording speed are subjected to the time-line display, side by side, in this case, some frames extracted and displayed are different between the moving images, and hence it is difficult to compare the moving images due to the display of different images at the corresponding frames.